Stump Grinder Bolts

[ROLLACOSTA]

How many of you guys are using a compressor and air impact wrench to un-do/do-up the bolts holding stump grinder teeth ???...How well dos this work??

For the guys using this method of doing up tiresome stumpcutter bolts what size wrench are you using [lbs/ nm] ?? is a wrench that delivers 450 ft-lb of torque adequete ??

Thanks for any relies

 

[Stump Man]

I use a t-bar with hex socket and 6' pipe to make sure they are tight after using air wrench.

 

[Menchhofer]

We have always used air wrench to tighten the allen bolts and it seems to work just fine for our smaller 4400. At times though, the impact wrench will not loosen the bolts and we usually use a allen wrench and cheater bar.

Friend of mine has a much LARGER machine and he uses the impact and then torques the bolts even more.

450lbs of torque isn't bad. Usually the maximum torque rating of an impact wrench is rated in reverse motion, not forward.

 

[Lumberjack]

We have used an impact wrench for 8 years, 450ft lbs is plenty of torque.

Few notes:

Overtorquing bolts doesnt help, using a 6' cheater bar is rediculous unless you are tightening a 3/4" or 1" bolt and weigh under 150 pounds.

We squirt WD 40 in the threaded teeth and the threads on the bolt, hand start them then run them home with the wrench. If the wrench has trouble like the threads are fouled (anything other than a quick blip that seats the bolt) we back it out and retighten it. That cleans the thread and offers better holding power and a more accurate torque load.

Dont tighten the first bolt until the second bolt is seated. Our method is thread both of the bolts, seat the first, seat and tighten the second, tighten the first and then go over both once again. Never fails. I can change the 12 main cutters on the RG50 or RG85 in under 20 minutes, assuming a head doesnt strip (proper bolt replacement keeps that from happening, as well as the proper upkeep to the tool).


I am not sure as to the ft/lbs to our wrench, I beleive its 650/450ft lbs. The compressor is 7hp, 80 gallon.

 

[ROLLACOSTA]

thanks for the replies guys

 

[Dadatwins]

I use a product called never-seize by permatex on my bolts. Works great to prevent frozen bolts. As for impact wrench I tighten with air- wrench, then bang pocket with dead-blow hammer and tighten again. I will usually get up to another 1/4 turn after hitting with hammer. On the bigger grinder I still sometimes have to use the breaker bar to get bolts started loose. Agree it is too easy to overtorque these bolts with 6' pipes and end up stripping out the heads. When the air wrench not available I use a 30" breaker bar with a socket for loosening and tightening and it works great too. Same system with breaker bar, tighen bolts, dead blow, tighten again.

Rolla, how is the new grinder working?

 

[DDM]

Touque Spec for a 5/8" Grade 8 Bolt is 215 FT Lb's. Run a few in and Test them with a torque wrench. If your getting a good 215 lb's Your Fine. Also Impact wrenches have more Reverse torque than forward.

http://dodgeram.org/tech/specs/bolts/SAE_bolts.html

 

[Aerial]

We us a 3/4'' air wrench "only" to do our's and have no problems taking them off or on. We do the same as Lumberjack when tightening them!

Aerial

 

[Proj Eng]

Good info DDM...
regarding torque specs:
any oil or compound will lower the final torque required (most are dry thread settings) for example, if 125 ft-lbs are req'd, then adding WD-40 or something equivalent will reduce that by 10% (so approx 112ft lbs)
Plain vs plated bolts makes a difference too (with plated being a lower torque value)
if you have time before removal, soak any bolt down with a penetrating oil, it does wonders.
and bolts stretch over time, so don't be afraid to replace them all every so often.